LOGITECH GAMING SOFTWARE 

Since there's no software CD in the bundle you will need to download the latest gaming software from the Logitech support page.

The Logitech Gaming Software shows a large keyboard picture from where you can click on the programmable buttons (G-Keys/Macros) to start configuring them.

Once you click on either of the keys the game profiler automatically scans to detect if you have one of the 260 supported games installed (each software update adds more games) and then loads the corresponding profiles.

So here you can assign one of the pre-configured commands to one of the G keys, use the command editor to create your own commands, set a millisecond delay when using a command with more than just 1 key and finally switch between profiles by clicking on the M1/M2/M3 keys.